As someone that shows western pleasure I'm throwing in my 2 cents. The horse clearly has flaws. He is not a good loper but obviously would look 10 times better a notch or 2 faster. His front legs are my peeve... When the inside leg doesn't reach. He's not using his shoulders. They have more emphasis on the speed and not the movement. Balance both speed and movement and you end up with a beautiful result (proving the horse is a good loper in the first place).
To the earlier post about horses moving sideways: The purpose is to get more drive out of both the hocks and get the shoulders working more. At least that's the original idea. When riders slack, then you get the sideways crap. The horse should have a bit of a bend (providing they keep the horses shoulder from dropping). It's not an easy move for the horse but the end result really is pretty (please don't throw things at me for saying that), however there's nothing better than seeing a horse be able to do it without getting the hip pushed in so much. Hello natural talent. Those are the horses though that win the world titles and obviously a majority don't have that. It's a way to work with what ya got. It's also a good way to teach a horse to drive... as you look at a senior western pleasure class, I bet you don't see that sideways stuff usually.
I accept that the western pleasure world has its flaws, but it's a blast to show. There's nothing I love more than to show my horse with the reins loose to his knees, head level, flat front legs, and his hocks DRIVING (but not sideways - never sideways haha). Don't let a few bad apples skew your opinion that everyone that shows wp rides their horse like that.
Now that youtube video that paintedpastures posted: BEAUTIFUL. I need to get me some more of that. :)